Köln - Red light district?

[kox]

Where is the "red light district" in the Koeln (Cologne)? What is the the street name?
One street, or small are, where working in a some peep show, and special germany brothel (It's
here where you find most girls at any given time sitting dressed up
in their rooms and waiting for customers. Admission normally is free, there are no doorkeepers)

[Harlequin]

https://www.6relax.de